The 100 wealthiest people on the planet added $380 million to their collective net worth after the Standard & Poor’s 500 Index reached its highest level since October 2007 this week.

Carlos Slim, the world’s richest man, shed $3.9 billion from his net worth as shares of America Movil SAB slid 10.8 percent after the mobile phone operator said slower economic growth in Mexico hurt revenue. Slim, 73, has a net worth of $74.1 billion, according to the Bloomberg Billionaires Index.

“One of the reasons why we haven’t declared victory and sold is because there’s a chance for continued investor risk-taking,” Jack Ablin, chief investment officer at BMO Private Bank in Chicago, which oversees about $66 billion in assets, said in a phone interview. “It’s entirely possible that more people like Dell, Buffett and others will exploit the valuation differential between stocks and bonds.”

The S&P 500 closed at 1519.79 yesterday, up 0.12 percent for the week. The index capped a seventh straight weekly gain, the longest streak in two years. Better-than-forecast manufacturing and consumer confidence data fueled optimism in the economy. The yen erased gains against the dollar as Group of 20 finance officials met in Moscow.

The MSCI World Index lost 0.25 percent during the week to close at 1406.92.

The 82-year-old’s Berkshire Hathaway Inc. and 3G Capital, an investment firm backed by three Brazilian billionaires -- Jorge Paulo Lemann, 73, and his partners Marcel Telles and Carlos Alberto Sicupira -- agreed to buy Pittsburgh-based HJ Heinz Co. for about $23 billion on Thursday. The trio have a combined net worth of $35.5 billion. Lemann is the country’s richest man.

The Bloomberg Billionaires Index takes measure of the world’s wealthiest people based on market and economic changes and Bloomberg News reporting. Each net worth figure is updated every business day at 5:30 p.m. in New York and listed in U.S. dollars.